shell 函数返回值与字典

shell的函数只能返回整数值，如果想让函数返回字符串可以在函数调用处为变量赋值。

# 定义函数
function test() {
    name=$1
    echo "123213"
}

# 调用函数，执行结果赋值给变量ret
ret=$(test "lishichao")
echo $ret


# 执行结果
[root@dev-test shell]# sh test.sh
123213

最近在写一键安装脚本，一个一个判断输入参数太麻烦，所以使用shell字典匹配对应函数。

function main(){
    if [[ $USER != "root" ]]
    then
        echo "Please use root account"
        exit
    fi
    if [[ -z $VAR ]]
    then
        echo "please input your action:pypy,nginx,redis,mysql,hall0,hall37"
        exit
    fi

    case $VAR in
        "pypy")
            install_pypy5
            ;;
        "nginx")
            nginx
            ;;
        "redis")
            install_redis
            ;;
        "mysql")
            install_mysql
            ;;
        "hall0")
            hall0
            ;;
        "hall37")
            hall37
            ;;
        *)
            echo "please  input your action:pypy,nginx,redis,mysql,hall0,hall37"
            ;;
    esac
}

main

使用case判断输入参数

function install_php() {
    echo "安装php7"
    exit 0
}

function install_filebeat() {
    echo "安装filebeat"
    exit 0
}

function install_rabbitmq() {
    echo "安装rabbitmq"
    exit 0
}

function install_logstash() {
    echo "安装logstash"
    exit 0
}

declare -A dic
dic=([php]=install_php [logstash]=install_logstash [filebeat]=install_filebeat)

VAR=$1
for key in $(echo ${!dic[*]})
do
    if [[ $VAR == $key ]];then
       ${dic[$VAR]}
       echo "$key"
    fi
done

echo "$(pwd)/$0 {pypy | nginx | redis | mysql | hall0 | hall37 | rabbitmq | logstash | filebeat}"

执行结果：

[root@dev-test shell]# sh test.sh
/opt/shell/test.sh {pypy | nginx | redis | mysql | hall0 | hall37 | rabbitmq | logstash | filebeat}

[root@dev-test shell]# sh test.sh logstash
安装logstash

[root@dev-test shell]# sh test.sh filebeat
安装filebeat